Neural mechanisms of auditory feedback during speech

描述（由申请人提供）：了解在说话过程中听觉反馈是如何被处理的，可以深入了解语音产生和感知的基本机制。这一知识也可能最终有助于早期发现并导致一些常见的临床疾病的治疗策略，其中听觉反馈异常处理的损伤已被报道（例如口吃，帕金森病，精神分裂症）。虽然许多行为学研究已经研究了听觉感知如何影响语言的产生，但直到最近，功能性神经影像学研究才开始研究语言的产生如何影响听觉感知的神经过程。最近的研究表明，在听觉皮层和颞上平面的其他区域，说话引起“说话诱发抑制”（SIS）：与来自外部来源的相同语音相比，对自己产生的语音的反应被抑制。在我们最近的工作中，我们已经表明，听力皮层中的SIS不是由于说话时该区域的整体抑制造成的。相反，SIS似乎是反馈预测误差（FPE）的神经关联——实际听觉输入与该听觉输入的内部“言语诱导预测”（SIP）之间的比较。SIS在听觉皮层的表达导致了一种假说，即SIS反映了对自身产生的外部刺激的听觉辨别（自我-非自我假说）。然而，行为研究和我们的初步数据支持了我们对语音运动控制中听觉反馈的理解的改进，表明SIS也可能反映了语音运动控制的反馈处理（语音运动控制假说）。我们已经开发了一个统一的概念模型，体现了这两个假设，我们提出的实验使用SIS来测试神经相关性和该模型的有效性。具体目的是确定SIS如何通过1)改变反馈，2)语音目标动态和3)语音运动适应来调节。这些操作不仅帮助我们揭示了SIS的功能意义，而且还帮助我们确定了SIS在颞上平面上的功能是否存在差异。此外，大脑其他部分的活动如何受到我们的实验操作的影响，将使我们能够确定产生SIS的机制的神经关联。我们的方法利用了功能磁共振成像（fMRI）和磁源成像（MSI）使用的独特的实时语音反馈改变方法。fMRI出色的空间分辨率将使我们能够重建与SIS和SIP相关的活动空间位置，而MSI出色的时间分辨率将使我们能够重建这些区域的激活序列。

DESCRIPTION (provided by applicant): Understanding how auditory feedback is processed during speaking provides insights into fundamental mechanisms underlying speech production and perception. This knowledge might also ultimately contribute to the early detection and lead to treatment strategies for a number of prevalent clinical conditions where impairments in abnormal processing of auditory feedback have been reported (e.g. stuttering, Parkinson's disease, schizophrenia). While many behavioral studies have examined how auditory perception affects speech production, only recently have functional neuroimaging studies begun examining how producing speech affects the neural processes serving auditory perception. Recent studies have shown that in auditory cortex and other areas in the superior temporal plane, speaking causes "speaking-induced suppression" (SIS): response to self-produced speech is suppressed when compared to identical speech from an external source. In our recent work, we have shown that SIS in auditory cortex does not result from overall inhibition of this area during speaking. Rather, SIS appears to be a neural correlate of a feedback prediction error (FPE) - a comparison between actual auditory input and an internal "speaking-induced prediction" (SIP) of that auditory input. SIS expression in auditory cortex has led to the hypothesis that SIS reflects auditory discrimination of self-produced from externally produced stimuli (Self-non-Self Hypothesis). However, refinements in our understanding of auditory feedback in speech motor control, that are supported by behavioral studies and our preliminary data, suggest that SIS may also reflect feedback processing for speech motor control (Speech Motor Control Hypothesis). We have developed a unifying conceptual model that embodies both hypotheses, and our proposed experiments use SIS to test the neural correlates and the validity of this model. The specific aims are to determine how SIS is modulated by 1) altered feedback, 2) speech target dynamics and 3) speech motor adaptation. These manipulations not only help us to unravel the functional significance of SIS but also help us determine if there is a differentiation of the function of SIS across the superior temporal plane. Furthermore, how activity in other parts of the brain is affected by our experimental manipulations will allow us to determine the neural correlates of the mechanisms that generate SIS. Our approach capitalizes on unique real-time speech feedback alteration methods used with functional magnetic resonance imaging (fMRI) and magnetic source imaging (MSI). The excellent spatial resolution of fMRI will enable reconstruction of spatial locations of activity related to SIS and SIP while the excellent temporal resolution of MSI will enable us to reconstruct the sequence of activation in these areas.